Viscosity responsive control



1966 w. F. ISLEY ETAL VISCOSITY RESPONSIVE CONTROL 2 Sheets-Sheet 1Original Filed April 25, 1962 NO! ESEL FUEL F O T m w T A 8 V Y 5 0 c sV GASOLINE HIGHER TING VALU (BTU/ NORMAL (ASSUMED SAME H.HvV AS GASOLININVENTORS VULUMET/F/C HEAT/1V6 VALUE N S m Z U BR D F C WK N HA Ann W FY ATTORNEYS Dec. 27, 1966 w. F. ISLEY ETAL VISCOSITY RESPONSIVE CONTROL2 Sheets-Sheet 2 Original Filed April 25, 1962 i0 VISCOSITY RESPONSIVE2e CONTROL DEVICE LK um FT w m m 0 S n N T. N .R v vl E E Z T W L U N Mam .0 W F. H C m m A L 2% F Y B United States Patent M 3,293,991VISCOSITY RESPGNSIVE CONTROL Walter F. Isley, Grosse Pointe, and FrankC. Druzynslki, Birmingham, Mich., assignors to Continental Aviation andEngineering Corporation, Detroit, Mich., a corporation of VirginiaOriginal application Apr. 23, 1962, Ser. No. 189,378, now Patent No.3,170,503, dated Feb. 23, 1965. Divided and this application Aug. 3,1964, Ser. No. 386,957

6 Claims. (Cl. 9152) This application is a division of our copendingapplication Ser. No. 189,378, filed April 23, 1962 now Patent No.3,170,503.

This invention relates to multifuel engines and more particularly to acontrol system for automatically varying the quantity of fuel for suchan engine to maintain a maximum power output for any fuel being used.

Multifuel engines are called upon to operate with fuels having widevariations in heating value per gallon. When equipped with conventionaltype injection systems which meter essentially a constant volume for anyfuel, the engine will produce a variation in maximum power proportionalto the equivalent heating value of the volume of the fuel injected.

An examination of the viscosity characteristics of fuels at varyingtemperatures shows a definite relationship between viscosity and fuelheating value. This viscosity characteristic is used as the sensedvariable in the fuel control system of the present invention. In thisway fuel is injected in quantities which will insure that maximum poweroutput will remain constant with any fuel being used.

It is an object of the present invention to obtain a constant maximumpower output for multifuel engines by providing a fuel control systemwhich varies the volume of fuel in relationship to its heating value pergallon.

It is another object of the present invention to provide a control forvarying the flow of fuels to a multifuel engine which utilizes theproportional relationship between the viscosity and the heating valueper gallon of the fuel being used.

It is yet another object of the present invention to reducemanufacturing costs for fuel control systems for multifuel engines byproviding a simply constructed, easily assembled and reliable controldevice.

Still further objects and advantages of the present invention will beapparent to one skilled in the art to which the invention pertains uponreference to the following drawings and description in which FIG. 1 is achart showing the relationship between viscosity and heating value forseveral types of fuels and at different temperatures.

FIG. 2 is a cross-sectional view of a preferred embodiment of thepresent invention.

FIG. 3 is a diagrammatic view illustrating the preferred relation of thecontrol to an engine.

FIG. 1 illustrates the relationship between the viscosity and heatingvalue of various fuels which is made use of in the present invention. Ascan be seen on this chart, the relationship is almost a single line forthe various hydrocarbon fuels that are shown. By sensing changes inviscosity in effect it is possible to also sense changes in the heatingvalue of the fuel being used.

The fuel viscosity responsive device of the present invention as canbest be seen in FIG. 2 preferably comprises a housing 11 provided withan inlet port 12 and a pair of parallel, bored portions 13 and 14. Thehousing 11 is capped at one end by a cap member 15 having a hollow, bossportion 16 which extends into the bored portion 13. The other end of thehousing '11 is closed 3,293,991 Patented Dec. 27, 1966 by an end member17 having a recess 18 which aligns with the :bored portion 13.

The inlet port 12 is adapted to be connected to a fuel pressure supplysuch as a pump A driven from an engine B as shown in FIG. 3, and directsthe flow of fuel into the bore portion 14. The bore portion 14 alignswith a recessed portion 19 in the cap member 15 to provide a controlchamber 20. The bore 14 and the recessed portion 19 carry a piston 21somewhat less in length than the chamber 20 and thus chambers 20A and20B are formed at each end of the piston 21. The piston 21 is providedwith a reduced portion 2 2 which provides variable communication betweenthe inlet port 12 and a passage 23 open to the opposite side of thechamber 20. In operation, the piston 21 is urged into a positionpermitting full flow of fuel between the inlet port 12 and the passage23 by a spring 24 seated in the recess 19. A passage 25 at all timesopenly connects the passage 23 to the chamber 20B. An outlet port 26connected to the fuel tank C, as seen in FIG. 3, communicates with thechamber 20A by means of an outlet passage 27 provided in the cap member15.

Fuel flows from the passage 23 into a peripheral chamber 28 formed byproviding a reduced portion 29 in the boss 16. The boss 16 is in eifecta piston in the bore 13 and is sufficiently small to provide aperipheral orifice '30 between the boss 16 and bore 13, permitting fuelto flow from the chamber 28 to a pressure chamber 31 formed by thehollow portion 32 of the boss 16 and an enlarged portion '33 provided inthe bore portion 13.

A passage 34 directs the fuel from the pressure cham ber 21 to theoutlet passage 27 and thence to the fuel tank C. An adjustable needlevalve 35 is provided to selectively restrict the flow of fuel from thepassage 34 to the outlet passage 27.

A diaphragm 36 is disposed intermediate the pressure chamber 31 and thealigned recess 18 provided in the end member 17. The diaphragm 36 ispositioned by a spring 37 carried in the recess 18. The diaphragm 36 isoperably connected to linkage 38 carrying a wedge shaped movable camblock 39. Injection pump control linkage 40 has an actuated element 40Bfrictionally engaging the block 39 and is operably connected by suitableelements 40C to the full load stop of the fuel pump A shown in FIG. 2.An escape passage 41 connects the recess portion 18 with the outletpassage 27.

In operation, fuel from the fuel pressure supply pump A is permitted toenter the inlet port 12. The piston 21 acts to reduce the pressure offuel in the chamber 28 to some constant value by balancing pressure inchamber 20B against fuel outlet pressure (substantially atmospheric)plus spring pressure. When the inlet pressure is greater than thatdesired, the excess pressure acts through the passage 25 and the chamber2013 to lift the piston 21, thereby tending to close communicationbetween the inlet port 12 and the passage 23. It should :be pointed outthat various pressure regulating mechanisms may be sufficient for thepurposes of the invention and the invention is not intended to belimited to the valve structure illustrated. The valve need not even .bea part of the housing but could be a separate structure fixed apart fromthe rest of the control mechanism. All that is necessary is that thefuel be reduced to a constant pressure before entering the chamber 28 sothat only changes in the viscosity of the fuel will be a determiningfactor and not changes in pressure produced by other variables.

The fuel then flows through the first orifice 30 formed by the bossportion 16 closely spaced from the bore 13. Fuel then flows to thesecond operative orifice which is the restriction formed by the needlevalve 35 disposed between the passage 34 and the outlet passage 27.These two orifices have widely different flow characteristics andtherefore have flow coefficients which change with viscosity changes sothat the pressure in the pressure chamber 31 will vary with theviscosity of the fuel. The position of the diaphragm 36 is thereforevaried in accordance with this fuel pressure change produced byviscosity changes. The diaphragm 36 is connected by suitable linkage 38to the wedge shaped cam block 39 which serves to vary the full load stopin the injection pump A. The amount of compensation required to maintainconstant power output over a range of fuels is easily obtained by aproper selection of the wedge angle of the block 39.

As is apparent from the chart shown in FIG. 1 fuel temperature affectsfuel viscosity and without the inclusion of some compensating featurefor this effect the general tendency of the control illustrated would beto increase the amount of fuel injected beyond the desired limits athigher than normal ambient temperatures and decrease the amount injectedbelow the desired limits at lower than normal temperatures. Tocompensate for these undesirable fuel temperature effects, a combinationof materials is selected for the piston like boss 16 and the housing 11that will provide a variance in the orifice 30 in response to changes inthe ambient temperatures of the fuel being used and in proportionscommensurate with the attendant engine fuel quantity demands. Forinstance the combination of a relatively high expansion material for theboss 16 and a relatively lower expansion material for the housing 11would reduce the orifice 30 with increased temperature and enlarge it atlower temperature. A reduction in size of the orifice 30 would reducethe pressure in chamber 31 and thus fuel flow to the engine B would bereduced. A combination of materials can be selected which will producean enlargement of the orifice at higher temperatures if this isdesirable when the sensing device is used for other purposes thancontrolling fuel injection. Thus the practical effect of ambienttemperature changes on a properly selected combinaton of materials forthe boss 16 and the housing 11 is to vary the degree of fuel quantityinjected in desired proportions to match engine requirements.

In the particular embodiment developed by us, the housing has beenconstructed of cast iron and the boss 16 of zinc. However, it isapparent that other material combinations could be used.

It is apparent that if the orifices 30 and the orifice formed by theneedle valve 35 are reversed in flow order, a reversed effect willresult. That is, the pressure in chamber 31 will increase with anincrease in the viscosity of the fuel being used.

It is also apparent that although a preferred use of the viscositysensing device has been described as a means by which the fuel flow maybe regulated in an internal combustion engine, other uses may also bemade of the present invention. For instance, the device could be used aseither a viscosity or heating value meter or sensor. Various otherchanges and modifications may be made without departing from the spiritof the invention or the scope of the appended claims.

We claim:

1. A viscosity sensing device comprising,

(a) a housing having an inlet and an outlet with said inlet beingadapted for connection to a source of fluid pressure,

(b) said housing having a first orifice formed by a pair of concentricradially spaced cylinders in communication with said inlet, theinnermost of said cylinders being hollow, and a second orifice disposeddownstream and in series flow with said first orifice, said outlet beingin communication with said second orifice,

(c) said housing having a chamber formed intermediate said first orificeand said second orifice and formed in part by the interior of saidinnermost cylinder and pressure sensing means disposed within saidchamber to sense pressure changes intermediate said orifices as producedby variations in fluid viscosity, and

(d) thedis'tance'between said cylinders which forms said first orificebeing less than the greatest transverse dimension of said secondorifice.

2. The viscosity sensing device as defined in claim 1 and in which saidcylinders forming said first orifice have different coefficients ofthermal expansion whereby to produce variation in the size of said firstorifice in response to temperature changes in the fluid delivered tosaid first orifice.

3. The device as defined in claim 2 and in which said differentcoefficients of thermal expansion of said cylinders produces reductionin the size of said first orifice with temperature increase.

4. The device as defined in claim 2 and in which said differentcoefficients of thermal expansion of said cylinders produces an increasein the size of said first orifice with temperature increase.

5. The device as defined in claim 1 and including means for manuallyadjusting the size of said second orifice.

6. The device as defined in claim 1 and including means disposedupstream of said first orifice and operable to regulate the pressure ofthe fluid delivered to said first orifice to a predetermined constantvalue.

References Cited by the Examiner UNITED STATES PATENTS 1,534,091 4/1925Smoot 15836 X 2,033,302 3/1936 Rockwell 73-56 2,400,910 5/1946 Booth7355 2,771,770 11/1956 Bouman 7355 2,859,768 11/1958 Teague 1374683,106,225 10/1963 Spurling 137468 X FOREIGN PATENTS 546,358 7/1942 GreatBritain.

WILLIAM F. ODEA, Primary Examiner.

ISADOR WEIL, Examiner.

H. WEAKLEY, Assistant Examiner.

1. A VELOCITY SENSING DEVICE COMPRISING, (A) A HOUSING HAVING AN INLETAND AN OUTLET WITH SAID INLET BEING ADAPTED FOR CONNECTION TO A SOURCETO FLUID PRESSURE, (B) SAID HOUSING HAVING A FIRST ORIFICE FORMED BY APAIR OF CONCENTRIC RADIALLY SPACED CYLINDERS IN COMMUNICATION WITH SAIDINLET, THE INNERMOST OF SAID CYLINDERS BEING HOLLOW, AND A SECONDORIFICE DISPOSED DOWNSTREAM AND IN SERIES FLOW WITH SAID FIRST ORIFICE,SAID OUTLET BEING IN COMMUNICATION WITH SAID SECOND ORIFICE, (C) SAIDHOUSING HAVING A CHAMBER FORMED INTERMEDIATE SAID FIRST ORIFICE AND SAIDSECOND ORIFICE AND FORMED IN PART BY THE INTERIOR OF SAID INNERMOSTCYLINDER AND PRESSURE SENSING MEANS DISPOSED WITHIN SAID CHAMBER TOSENSE PRESSURE CHANGES INTERMEDIATE